POLITICAL poll taking in recent years has proved considerably more reliable than oneiromancy, haruspication or the casting of rune stones. George Gallup has erred in his election polls by only 1.5% since 1954. Yet last week, Gallup and Louis Harris published such divergent interpretations of the preconvention G.O.P. standings that Gallup's son and partner, George Jr., admitted that the psephologists were facing "a credibility-gap problem."
Gallup's survey showed Richard Nixon defeating both Hubert Humphrey and Eugene McCarthy for the presidency. If the election took place at the time of the poll, Nixon would win, Gallup said, by two points over Humphrey and by five points over McCarthy. The sampling suggested that Nelson Rockefeller would merely tie Humphrey and defeat McCarthy by one percentage point of the vote.
Rocky's camp countered with a commissioned sampling by another veteran pollster, Archibald Crossley, who had surveyed the nation's nine major industrial states and found that the New Yorker could easily coast past both the Democrats, while Nixon would tie with McCarthy and defeat Humphrey by only three points.
Chorus of Hoots. Then Louis Harris published an independent national survey showing Rockefeller six points ahead of both Humphrey and McCarthy. Nixon, said Harris, would lose to Humphrey by five points and to McCarthy by eight. The wide discrepancies in the samplings brought a chorus of hoots—especially, of course, from the Nixon camp.
The nation's major pollsters have been in contact with one another since last June, when they formed the National Committee on Published Polls to publicize standards for their opinion surveys. Last week, when their contradictory reports appeared, Harris called George Gallup Jr., whose famous father was traveling in Europe, and persuaded him to join in an unprecedented joint public statement. After consulting Crossley, they issued a complicated collective verdict. If their three polls were "plotted out sequentially, as though they were conducted by a single organization, using the same sampling techniques and the same question-asking techniques," they concluded, then 1) a Nixon-Humphrey race would be extremely close, "with Wallace perhaps holding the balance"; 2) "Rockefeller has now moved to an open lead over his possible Democratic opponents, Humphrey and McCarthy"; and 3) "the McCarthy vote has shown and continues to show the greatest amount of volatility among the four leading candidates."
Error Margin. To justify the apparent turnabout, Gallup suggested that the timing of the poll taking was crucial. Gallup's sampling was made between July 19 and 21, just after Dwight Eisenhower endorsed Nixon. Ike's announcement may have swung some sentiment to his former Vice President.
Crossley's poll was taken between July 21 and 26, and Harris' between July 26 and 29. Some analysts point out that as Harris was doing his sampling, Rockefeller's saturation advertising and personal campaign activity was reaching a peak, while Nixon was vacationing briefly and Humphrey was recovering from the flu.